scholarly journals Short-Term Tea Consumption Is Not Associated with a Reduction in Blood Lipids or Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

2020 ◽  
Vol 150 (12) ◽  
pp. 3269-3279
Author(s):  
Ebuwa Igho-Osagie ◽  
Kelly Cara ◽  
Deena Wang ◽  
Qisi Yao ◽  
Laura P Penkert ◽  
...  

ABSTRACT Background A recent systematic review of epidemiological evidence suggests that higher amounts of tea intake are associated with lower risks of cardiovascular disease (CVD) incidence and mortality. Objectives Our study objective was to assess mechanisms by which tea consumption may influence CVD risks. Methods A systematic review and meta-analysis was conducted to investigate the effects of green and/or black tea consumption (≥4 wk) on systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride (TG) in healthy populations and among at-risk adults (analyzed separately) with metabolic syndrome, prediabetes, and hypercholesterolemia. The Grading of Recommendations Assessment, Development and Evaluation approach was used to rate the strength of evidence (SoE). Results A total of 14 unique RCTs which randomly assigned 798 participants to either green tea, black tea, or placebo controls were included in our analyses. Intervention durations ranged from 4 to 24 wk (mean: 7.4 wk). Individual studies were judged as moderate to high quality based on risk of bias assessments. SoE was low to moderate owing to low sample sizes and insufficient power for most included studies to observe changes in the measured CVD biomarkers. Meta-analyses showed no significant effects of tea consumption on SBP, DBP, total cholesterol, LDL cholesterol, HDL cholesterol, and TG in healthy and at-risk adults (i.e., adults with obesity, prediabetes, borderline hypercholesterolemia, and metabolic syndrome). Conclusions Short-term (4–24 wk) tea consumption does not appear to significantly affect blood pressure or lipids in healthy or at-risk adults, although the evidence is limited by insufficient power to detect changes in these CVD biomarkers. High-quality RCTs with longer durations and sufficient sample sizes are needed to fully elucidate the effects of tea. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42020134513.

2020 ◽  
Vol 27 ◽  
Author(s):  
Peyman Nowrouzi-Sohrabi ◽  
Reza Tabrizi ◽  
Mohammad Jalali ◽  
Navid Jamali ◽  
Shahla Rezaei ◽  
...  

Introduction: A systematic review and meta-analysis of clinical trials was undertaken to evaluate the effect of diacerein intake on cardiometabolic profiles in patients with type 2 diabetes mellitus (T2DM). Methods: Electronic databases such as PubMed, EMBASE, Scopus, Web of Science, Google Scholar, and Cochrane Central Register of Controlled Trials were searched from inception to 31 July 2019. Statistical heterogeneity was evaluated using Cochran’s Q test and I-square (I2 ) statistic. Data were pooled using random-effect models and weighted mean difference (WMD). Results: From 1,733 citations, seven clinical trials were eligible for inclusion and meta-analysis. A significant reduction in hemoglobin A1c (HbA1c) (WMD -0.73; 95%CI -1.25 to -0.21; P= 0.006; I2 = 72.2%) and body mass index (BMI) (WMD -0.55; 95%CI -1.03 to -0.07; P= 0.026; I2 = 9.5%) were identified. However, no significant effect of diacerein intake was identified on fasting blood sugar (FBS) (WMD - 9.00; 95%CI -22.57 to 4.57; P= 0.194; I2 = 60.5%), homeostatic model assessment for insulin resistance (HOMA-IR) (WMD 0.39; 95%CI 0.95 to 1.73; P= 0.569; I2 = 2.2%), body weight (WMD -0.54; 95%CI -1.10 to 0.02; P= 0.059), triglycerides (WMD -0.56; 95%CI -24.16 to 23.03; P= 0.963; I2 = 0.0%), total-cholesterol (WMD -0.21; 95%CI -12.19 to 11.78; P= 0.973; I2 = 0.0%), HDL-cholesterol (WMD -0.96; 95%CI -2.85 to 0.93; P= 0.321; I2 = 0.0%), and LDL-cholesterol levels (WMD -0.09; 95%CI -8.43 to 8.25; P= 0.983; I2 = 37.8%). Conclusion: Diacerein intake may reduce HbA1c and BMI; however, no evidence of effect was observed for FBS, HOMA-IR, body weight, triglycerides, total-cholesterol, HDL-cholesterol or LDL-cholesterol.


2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Lijun Zhang ◽  
Yangyang Wang ◽  
Lianlian Xiong ◽  
Yanfang Luo ◽  
Zhijun Huang ◽  
...  

Abstract Background Patients with chronic kidney disease (CKD) have a high prevalence of cardiovascular diseases, which often lead to physical inactivity that correlates with CKD exacerbation. The benefits of regular exercise to cardiovascular health have been well established in healthy population and highly suggestive in patients with CKD. To further strengthen the evidence base for the management of CKD, this meta-analysis was performed to systematically evaluate the effects of exercise therapy on renal function, blood pressure, blood lipid and body mass index (BMI) in non-dialysis CKD patients. Methods This meta-analysis was conducted following a previous protocol. Randomized controlled trials (RCTs) examining the effects of exercise therapy in non-dialysis CKD patients were searched in Pubmed, Embase, Cochrane Library, and three major Chinese biomedical databases (CNKI, WANGFANG and VIP) from their start date to October 30th, 2018. The Cochrane systematic review methods were applied for quality assessment and data extraction, and Revman version 5.3 was used for systematic review and meta-analysis. Results 13 RCTs, representing 421 patients with non-dialysis CKD, were included in this meta-analysis. Compared to the controls, exercise therapy brought an increase in eGFR (MD = 2.62, 95% CI:0.42 to 4.82, P = 0.02, I2 = 22%), and decreases in systolic blood pressure (SBP) (MD = -5.61, 95% CI:-8.99 to − 2.23, P = 0.001, I2 = 44%), diastolic blood pressure (DBP) (MD = -2.87, 95% CI:-3.65 to − 2.08, P < 0.00001, I2 = 16%) and BMI (MD = -1.32, 95% CI:-2.39 to − 0.25, P = 0.02, I2 = 0%) in non-dialysis CKD patients. Exercise therapy of short-term (< 3 months) decreased triglyceride (TG) level (P = 0.0006). However, exercise therapy did not significantly affect serum creatinine (SCr), total cholesterol (TC), high density lipoprotein (HDL) or low density lipoprotein (LDL) in non-dialysis CKD patients. Conclusion Exercise therapy could benefit non-dialysis CKD patients by increasing eGFR while reducing SBP, DBP and BMI. Additionally, short-term intervention of exercise could decrease TG.


2018 ◽  
Vol 9 (12) ◽  
pp. 6307-6314 ◽  
Author(s):  
Adilah F. Ahmad ◽  
Lisa Rich ◽  
Henrietta Koch ◽  
Kevin D. Croft ◽  
Mario G. Ferruzzi ◽  
...  

Addition of milk to black tea alters the acute/short-term benefical effect of regular black tea consumption on vascular function and blood pressure.


2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Ding Ding Wang ◽  
Aedin Cassidy ◽  
Mario G. Ferruzzi ◽  
Paul Jacques ◽  
Elizabeth Johnson ◽  
...  

AbstractThere is increasing evidence that both black and green tea are beneficial for prevention of cardiovascular disease (CVD). We conducted a systematic review and meta-analysis evaluating the effects of tea flavonoids on cardiovascular (CVD) and all-cause mortality outcomes.Searches across five databases including PubMed and Embase were conducted through November 2018 to identify randomized controlled trials (RCTs) and prospective cohort studies reporting cardiovascular and all-cause mortality outcomes. Two investigators independently conducted abstract and full-text screenings, data extractions, and risk of bias (ROB) assessments using the Nutrition Evidence Library Bias Assessment Tool (NEL BAT). Mixed-effects dose-response meta-regression and standard random-effects meta-analyses for outcomes with ≥ 4 studies were performed. 0 RCTs and 38 prospective cohort studies were included in the systematic review. NEL BAT scores ranged from 0–15 (0 being the lowest risk). Our linear meta-regression model showed that each cup increase in daily tea consumption (about 280 mg and 338 mg of total flavonoids for black and green tea, respectively) was associated with 3–4% lower risk of CVD mortality (predicted adjusted RR = 0.96; CI 0.93–0.99 for green tea and RR = 0.97; CI 0.94–0.99 for black tea). Furthermore, eachcup increase in daily tea consumption was associated a 2% lower risk of all-cause mortality (predicted adjusted relative risk (RR) = 0.98; 95% CI 0.97–0.99 for black tea and RR = 0.98; CI 0.96–0.99 for green tea, respectively). Two studies reported multivariable Cox regression analysis results for the relationship between black tea intake and risks of all-cause mortality outcomes. The results from these two studies were combined with our linear meta-regression result in a random-effects model meta-analysis and showed that each cup increase in daily black tea consumption was associated with an average of 3% lower risk of all-cause mortality (pooled adjusted RR = 0.97; 95% CI 0.87- 1.00) with large heterogeneity (I2 = 81.4%; p = 0.005). Current evidence indicates that increased tea consumption may reduce cardiovascular and all-cause mortality in a dose-response manner. This systematic review was registered on PROSPERO.


2018 ◽  
Vol 108 (3) ◽  
pp. 576-586 ◽  
Author(s):  
Lukas Schwingshackl ◽  
Georg Hoffmann ◽  
Khalid Iqbal ◽  
Carolina Schwedhelm ◽  
Heiner Boeing

ABSTRACT Background In previous meta-analyses of prospective observational studies, we investigated the association between food groups and risk of chronic disease. Objective The aim of the present network meta-analysis (NMA) was to assess the effects of these food groups on intermediate-disease markers across randomized intervention trials. Design Literature searches were performed until January 2018. The following inclusion criteria were defined a priori: 1) randomized trial (≥4 wk duration) comparing ≥2 of the following food groups: refined grains, whole grains, nuts, legumes, fruits and vegetables, eggs, dairy, fish, red meat, and sugar-sweetened beverages (SSBs); 2) LDL cholesterol and triacylglycerol (TG) were defined as primary outcomes; total cholesterol, HDL cholesterol, fasting glucose, glycated hemoglobin, homeostasis model assessment insulin resistance, systolic and diastolic blood pressure, and C-reactive protein were defined as secondary outcomes. For each outcome, a random NMA was performed, and for the ranking, the surface under the cumulative ranking curves (SUCRA) was determined. Results A total of 66 randomized trials (86 reports) comparing 10 food groups and enrolling 3595 participants was identified. Nuts were ranked as the best food group at reducing LDL cholesterol (SUCRA: 93%), followed by legumes (85%) and whole grains (70%). For reducing TG, fish (97%) was ranked best, followed by nuts (78%) and red meat (72%). However, these findings are limited by the low quality of the evidence. When combining all 10 outcomes, the highest SUCRA values were found for nuts (66%), legumes (62%), and whole grains (62%), whereas SSBs performed worst (29%). Conclusion The present NMA provides evidence that increased intake of nuts, legumes, and whole grains is more effective at improving metabolic health than other food groups. For the credibility of diet-disease relations, high-quality randomized trials focusing on well-established intermediate-disease markers could play an important role. This systematic review was registered at PROSPERO (www.crd.york.ac.uk/PROSPERO) as CRD42018086753.


PLoS ONE ◽  
2014 ◽  
Vol 9 (7) ◽  
pp. e103247 ◽  
Author(s):  
Arno Greyling ◽  
Rouyanne T. Ras ◽  
Peter L. Zock ◽  
Mario Lorenz ◽  
Maria T. Hopman ◽  
...  

Author(s):  
Reza Tabrizi ◽  
Eghbal Sekhavati ◽  
Peyman Nowrouzi-Sohrabi ◽  
Shahla Rezaei ◽  
Parinaz Tabari ◽  
...  

Background: Several studies have investigated the effect of Urtica dioica (UD) consumption on metabolic profiles in patients with type 2 diabetes mellitus (T2DM); however, the findings are inconsistent. This systematic review and meta-analysis of clinical trials was performed to summarize the evidence of the effects of UD consumption on metabolic profiles in patients with T2DM. Methods: Eligible studies were retrieved from searches of PubMed, Embase, Scopus, Web of Science, Cochrane Library and Google Scholar databases until December 2019. Cochran (Q) and I-square statistics were used to examine heterogeneity across included clinical trials. Data were pooled by using fixed-effect or random-effects model and expressed as weighted mean difference (WMD) and 95% confidence interval (CI). Results: Among 1485 citations, thirteen clinical trials were found to be eligible for the current meta-analysis. UD consumption significantly decreased levels of fasting blood glucose (FBG) (WMD= -17.17 mg/dl, 95% CI: -26.60, -7.73, I2= 93.2%), hemoglobin A1c (HbA1c) (WMD= -0.93, 95% CI: -1.66, -0.17, I2= 75.0%), C-reactive protein (CRP) (WMD= -1.09 mg/dl, 95% CI: -1.64, -0.53, I2= 0.0%), triglycerides (WMD = -26.94 mg/dl, 95 % CI = [-52.07, -1.82], P = 0.03, I2 = 90.0%), systolic blood pressure (SBP) (WMD= -5.03 mmHg, 95% CI = -8.15, -1.91, I2= 0.0%) in comparison to the control groups. UD consumption did not significantly change serum levels of insulin (WMD= 1.07 μU/ml, 95% CI: -1.59, 3.73, I2= 63.5%), total-cholesterol (WMD= -6.39 mg/dl, 95% CI: -13.84, 1.05, I2= 0.0%), LDL-cholesterol (LDL-C) (WMD= -1.30 mg/dl, 95% CI: -9.95, 7.35, I2= 66.1%), HDL-cholesterol (HDL-C) (WMD= 6.95 mg/dl, 95% CI: -0.14, 14.03, I2= 95.4%), body max index (BMI) (WMD= -0.16 kg/m2, 95% CI: -1.77, 1.44, I2= 0.0%), and diastolic blood pressure (DBP) (WMD= -1.35 mmHg, 95% CI: -2.86, 0.17, I2= 0.0%) among patients with T2DM. Conclusion: UD consumption may result in an improvement in levels of FBS, HbA1c, CRP, triglycerides and SBP, but did not affect on levels of insulin, total-, LDL-, and HDL-cholesterol, BMI, and DBP in patients with T2DM.


2021 ◽  
Author(s):  
Chang Ma ◽  
Xuehui Zheng ◽  
Yi Yang ◽  
Peili Bu

The main goal of this work was to clarify the effects of black tea supplementation on blood pressure by performing a systematic review according to the PRISMA guidelines, followed by a dose–response meta-analysis of randomized controlled trials.


1997 ◽  
Vol 78 (1) ◽  
pp. 41-55 ◽  
Author(s):  
S. A. Bingham ◽  
H. Vorster ◽  
J. C. Jerling ◽  
E. Magee ◽  
A. Mulligan ◽  
...  

Thirty-one men (47 (SD 14) years) and thirty-four women (35 (SD 13) years) took part in a 4-week randomized cross-over trial to compare the effect of six mugs of black tea daily v. placebo (water, caffeine, milk and sugar) on blood lipids, bowel habit and blood pressure, measured during a run-in period and at the end of weeks 2, 3 and 4 of the test periods. Compliance was established by adding a known amount of p–aminobenzoic acid (PABA) to selected tea bags, and then measuring its excretion in urine. Mean serum cholesterol values during run-in, placebo and on tea drinking were 5·67 (SD 1·05), 5·76 (SD 1·11) and 5·69 (SD 1·09)mmol/l (P=0·16). There were also no significant changes in diet, LDL-cholesterol, HDL-cholesterol, triacylglycerols, and blood pressure in the tea intervention period compared with placebo. Compared with placebo, stool consistency was softened with tea (P=0·04), and no other differences were found in bowel habit. Results were unchanged when fifteen ‘non-compliers’, whose PABA excretion indicated that fewer than six tea bags had been used, were excluded from the analysis, and when differences between run-in and tea periods were considered separately for those who were given tea first or second.


2021 ◽  
Vol 9 ◽  
Author(s):  
Angelo Zinellu ◽  
Panagiotis Paliogiannis ◽  
Alessandro G. Fois ◽  
Paolo Solidoro ◽  
Ciriaco Carru ◽  
...  

Lipid profile alterations have been observed in patients with coronavirus disease 2019 (COVID-19) in relation to disease severity and mortality. We conducted a systematic review and meta-analysis with meta-regression of studies reporting total, HDL, and LDL-cholesterol, and triglyceride concentrations in hospitalized patients with COVID-19. We searched PubMed, Web of Science and Scopus, between January 2020 and January 2021, for studies describing lipid concentrations, COVID-19 severity, and survival status (PROSPERO registration number: CRD42021253401). Twenty-two studies in 10,122 COVID-19 patients were included in the meta-analysis. Pooled results showed that hospitalized patients with severe disease or non-survivor status had significantly lower total cholesterol (standardized mean difference, SMD = −0.29, 95% CI −0.41 to −0.16, p &lt; 0.001), LDL-cholesterol (SMD = −0.30, 95% CI −0.41 to −0.18, p &lt; 0.001), and HDL-cholesterol (SMD = −0.44, 95% CI −0.62 to −0.26, p &lt; 0.001), but not triglyceride (SMD = 0.04, 95% CI −0.10 to −0.19, p = 0.57), concentrations compared to patients with milder disease or survivor status during follow up. Between-study heterogeneity was large-to-extreme. In sensitivity analysis, the effect size of different lipid fractions was not affected when each study was in turn removed. The Begg's and Egger's t-tests did not show evidence of publication bias, except for studies investigating LDL-cholesterol. In meta-regression, significant associations were observed between the SMD of LDL-cholesterol and age and hypertension, and between the SMD of triglycerides and study endpoint and aspartate aminotransferase. In our systematic review and meta-analysis, lower total, HDL, and LDL-cholesterol, but not triglyceride, concentrations were significantly associated with COVID-19 severity and mortality. Cholesterol concentrations might be useful, in combination with other clinical and demographic variables, for risk stratification and monitoring in this group.Systematic Review Registration: PROSPERO registration number: CRD42021253401.


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